Lenses, systems and methods for providing binocular customized treatments to correct presbyopia

ABSTRACT

An apparatus, such as lenses, a system and a method for providing custom ocular aberrations that provide higher visual acuity. The apparatus, system and method include inducing rotationally symmetric aberrations along with an add power in one eye and inducing non-rotationally symmetric aberrations along with an add power in the other eye to provide improved visual acuity at an intermediate distance.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority to U.S. provisional application No.61/733,292 filed on Dec. 4, 2012, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates generally to correction of eye defects, and morespecifically, to a system, method and apparatus for providing binocularcustomized treatments for remedying presbyopia.

Description of the Related Art

Surgery on the human eye has become commonplace in recent years. Manypatients pursue eye surgery as an elective procedure to treat an adverseeye condition, such as to avoid the use of contact lenses or glasses.One eye condition that can be treated surgically is presbyopia. Apatient suffering from presbyopia lacks the capability of the eye lensto accommodate or bend and thus to see at far distance and at neardistance. Presbyopia can be induced by age and/or pseudophakia (acondition in which a natural lens has been replaced with an intraocularlens).

Several treatment options are available for presbyopia. For example,multifocal intraocular lenses, extended depth of focus lenses, cornealinlays or other accommodating intraocular lenses can be surgicallyimplanted in the eye of a patient suffering from presbyopia to allow thepatient to focus and refocus between near and far objects. Anothertreatment option available to patients suffering from presbyopia isbased on monovision. In this option, generally the dominant eye istargeted for distant vision and the non-dominant eye is targeted fornear vision. This can be achieved by implanting the dominant eye with anintraocular lens (IOL) having a power that achieves plano refractionsuch that the dominant eye has no refractive error and by implanting thenon-dominant eye with an IOL that has an add power between 1.0-2.0Diopter over the dominant eye.

However, such an approach can result in sub-optimal intermediate visionif the non-dominant eye is targeted for near vision or sub-optimal nearvision if the non-dominant eye is targeted for intermediate vision.Additionally, some patients may not tolerate the refractive differencesin the dominant and non-dominant eye.

SUMMARY OF THE INVENTION

Multifocal intraocular lenses (IOLs) providing two or more opticalpowers, for example, one for near vision and one for distant vision, canbe implanted in the eye of a patient suffering from presbyopia toovercome some of the disadvantages of monovision. Although multifocalIOLs can lead to improved quality of vision for many patients, somepatients can experience undesirable visual effects (dysphotopsia), e.g.glare or halos. For example, if light from a distant point source isimaged onto the retina by the distant focus of a multifocal IOL, thenear focus of the multifocal IOL will simultaneously superimpose adefocused image on top of the image formed by the distant focus. Thisdefocused image may manifest itself in the form of a ring of lightsurrounding the in-focus image, and is referred to as a halo.Rotationally symmetric multifocal designs present symmetric halo shapes,while non-rotationally symmetric multifocal lenses present asymmetrichalos. Additionally, intermediate vision may be compromised inmultifocal IOLs that are configured to provide near and distant vision.

Thus, there exists a need for an ophthalmic solution that providesimproved vision at all of near, far and intermediate distances whilereducing dysphotopsia. One approach to provide improved vision at all ofnear, far and intermediate distances while reducing dysphotopsia can bea lens with an extended depth of focus. Without subscribing to anyparticular, a lens with an extended depth of focus can image objectswith a certain distance of its focal point with acceptable sharpness onthe retina. Thus, an extended depth of focus lens can produce imageswith acceptable sharpness for objects located at intermediate to fardistances or for objects located at near to intermediate distances.Various techniques for extending the depth of focus of a lens have beenproposed. For example, some approaches are based on intraocular lenseswith refractive or diffractive zones with different powers.

The embodiments disclosed herein include various ophthalmic lenssolutions (such as, for example, contact lenses, IOLs, phakic IOLs,corneal inlays, as well as corneal reshaping procedures such as, lasertreatments, or combinations of thereof etc.) for treating ophthalmicconditions in both eyes to enhance visual acuity at near, intermediateand far distances, and therefore provide a full range of vision. Invarious embodiments disclosed herein, binocular extension of depth offocus is achieved by inducing rotationally symmetric aberrations (e.g.fourth and/or higher order spherical aberrations) in one eye and byinducing non-rotationally symmetric aberrations (e.g. astigmatism, comaand/or trefoil) in the other eye to enhance visual acuity at anintermediate distance. In another aspect, binocular extension of depthof focus is achieved by a rotationally symmetric diffractive lenssolution in one eye and a rotationally asymmetric diffractive lenssolution in the other eye. In another aspect, binocular extension ofdepth of focus is achieved by a rotationally symmetric refractive lenssolution in one eye and a rotationally asymmetric refractive lenssolution in the other eye. In another aspect, visual acuity at anintermediate distance can be enhanced by applying scaled version ofnatural aberrations that are present in the patient's eye, as referredin U.S. patent application Ser. No. 13/690,505 filed on Nov. 30, 2012and entitled Lenses, Systems and Methods For Providing Custom AberrationTreatments And Monovision To Correct Presbyopia which is incorporatedherein by reference, in addition to inducing rotationally symmetric andasymmetric aberrations. In an alternative embodiment, the aberrationpatterns (e.g. fourth and/or higher order spherical aberrations andastigmatism, coma and/or trefoil) may also be imposed on the top ofmonovision, achieved with either refractive or diffractive techniques oron the top of a mix and match of multifocal or extended depth of focuslenses, which may also combine symmetric and asymmetric conceptsbinocularly.

In various embodiments, a binocular vision simulator can be used todetermine the amount and type of aberrations to be induced in each eye.The combination that provides the best through focus performance as wellas the patient's comfort is chosen. An example method of implementingthe concepts discussed herein includes: (i) determining with a binocularvision simulator a first amount of rotationally symmetric ornon-rotationally symmetric aberration which provides visual acuity forintermediate and distant vision in a first eye; (ii) determining withthe binocular vision simulator a second amount of rotationally symmetricor non-rotationally symmetric aberration which provides visual acuityfor intermediate and near vision in a second eye; (iii) applying thefirst amount of rotationally symmetric or non-rotationally symmetricaberration in the first eye; and (iv) applying the second amount ofnon-rotationally symmetric or rotationally symmetric aberration in thesecond eye, wherein a rotationally symmetric aberration pattern isapplied to the second eye if a non-rotationally symmetric aberrationpattern is applied to the first eye and vice-versa. Binocular visualacuity or just visual perception at different defocus position may betested in those conditions. The test may also be performed in thepresence of rotationally symmetric and asymmetric diffractive profilesonce applied using the binocular visual simulator, with a goal ofdetermining the combination of aberrations and diffractive ophthalmicsolutions which provide a continuous range of vision.

Various embodiments disclosed herein include lenses, methods and systemsthat can correct presbyopia by extending the depth of focus for lensesthat are configured to provide distant or near vision such that improvedintermediate vision is provided by binocular summation.

BRIEF DESCRIPTION OF THE DRAWINGS

Understanding of the present invention will be facilitated byconsideration of the following detailed description of the preferredembodiments of the present invention taken in conjunction with theaccompanying drawings, in which like numerals refer to like parts, andin which:

FIG. 1 is a diagram illustrating the relevant structures and distancesof the human eye.

FIGS. 2A and 2B are flowcharts of an implementation of a method used todetermine the combination of aberrations that can be induced to providevision acuity at near, far and intermediate distances.

FIG. 3 is a diagram illustrating aspects of a system that can be used toimplement the method described in FIG. 2.

FIG. 4A1-4A5 shows various embodiments of lenses having rotationallyasymmetric diffractive features.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

It is to be understood that the figures and descriptions of the presentinvention have been simplified to illustrate elements that are relevantfor a clear understanding of the present invention, while eliminating,for the purpose of clarity, many other elements found in typical lenses,lens systems and lens design methods. Those of ordinary skill in thearts can recognize that other elements and/or steps are desirable andmay be used in implementing the embodiments described herein.

The embodiments described herein are directed to an ophthalmic lens,such as an intraocular lens (IOL), or a corneal implant, and othervision correction methodologies, such as laser treatments, and a systemand method relating to same, for providing rotationally symmetricaberration patterns in one eye and non-rotationally symmetric aberrationpatterns in the other eye in order to induce a binocular customizedtreatment that achieves visual acuity at a range of distances.

The terms “power” or “optical power” are used herein to indicate theability of a lens, an optic, an optical surface, or at least a portionof an optical surface, to redirect incident light for the purpose offorming a real or virtual focal point. Optical power may result fromreflection, refraction, diffraction, or some combination thereof and isgenerally expressed in units of Diopters. One of ordinary skill in theart will appreciate that the optical power of a surface, lens, or opticis generally equal to the reciprocal of the focal length of the surface,lens, or optic, when the focal length is expressed in units of meters.

FIG. 1 is a schematic drawing of a human eye 200. Light enters the eyefrom the left of FIG. 1, and passes through the cornea 210, the anteriorchamber 220, a pupil defined by the iris 230, and enters lens 240. Afterpassing through the lens 240, light passes through the vitreous chamber250, and strikes the retina 260, which detects the light and converts itto a signal transmitted through the optic nerve to the brain (notshown). Cornea 210 has corneal thickness (CT), which is the distancebetween the anterior and posterior surfaces of the center of the cornea210. Anterior chamber 220 has an anterior chamber depth (ACD), which isthe distance between the posterior surface of the cornea 210 and theanterior surface of the lens 240. Lens 240 has lens thickness (LT) whichis the distance between the anterior and posterior surfaces of the lens240. The eye has an axial length (AXL) which is the distance between thecenter of the anterior surface of the cornea 210 and the fovea of theretina 260, where the image is focused.

The anterior chamber 220 is filled with aqueous humor, and opticallycommunicates through the lens 240 with the vitreous chamber 250. Thevitreous chamber 250 is filled with vitreous humor and occupies thelargest volume in the eye. The average adult eye has an ACD of about3.15 mm, although the ACD typically shallows by about 0.01 mm per year.Further, the ACD is dependent on the accommodative state of the lens,i.e., whether the lens 240 is focusing on an object that is near or far.

The quality of the image that reaches the retina is related to theamount and type of optical aberrations that each patient's eye presents.The ocular surfaces that generally contribute to ocular aberrations arethe anterior cornea and the lens. Although, all optical aberrations willaffect the quality (e.g. blur) of the image produced on the eye, someaberrations do not necessarily affect the sharpness and the clarity ofthe object as seen by the patient due to neural compensation. Variousembodiments described herein take into account the neural compensationthat allows a patient to perceive objects sharply and clearly even inthe presence of optical aberrations.

The term “near vision,” as used herein, refers to vision provided by atleast a portion of the natural lens in a phakic eye or an intraocularlens in a pseudophakic eye, wherein objects relatively close to apatient are substantially in focus on the retina of the patient's eye.The term “near vision” generally corresponds to the vision provided whenobjects are at a distance from the patient's eye of between about 25 cmto about 50 cm. The term “distant vision” or “far vision,” as usedherein, refers to vision provided by at least a portion of the naturallens in a phakic eye or an intraocular lens in a pseudophakic eye,wherein objects relatively far from the patient are substantially infocus on the retina of the patient's eye. The term “distant vision”generally corresponds to the vision provided when objects are at adistance of at least about 2 m or greater. As used herein, the “dominanteye” is defined as the eye of the patient that predominates for distantvision, as defined above. The term “intermediate vision,” as usedherein, refers to vision provided by at least a portion of the naturallens in a phakic eye or an intraocular lens in a pseudophakic eye,wherein objects at an intermediate distance from the patient aresubstantially in focus on the retina of the patient's eye. Intermediatevision generally corresponds to vision provided when objects are at adistance of about 2 m to about 50 cm from the patient's eye.

As used herein, an IOL refers to an optical component that is implantedinto the eye of a patient. The IOL comprises an optic, or clear portion,for focusing light, and may also include one or more haptics that areattached to the optic and serve to center the optic in the eye betweenthe pupil and the retina along an optical axis. In variousimplementations, the haptic can couple the optic to zonular fibers ofthe eye. The optic has an anterior surface and a posterior surface, eachhaving a particular shape that contributes to the refractive propertiesof the lens.

In the embodiments disclosed herein aberrations and/or additionaloptical power are provided in a patient's dominant and non-dominant eyeto increase depth of focus and to provide improved distant, near andintermediate vision. In some embodiments, rotationally and/ornon-rotationally symmetric aberrations can be induced in the patient'sdominant and/or non-dominant eye, such that the patient is able to havevisual acuity for a wide range of distances. In some embodiments, anoptical add power between about +0.5 Diopters and +2.0 Diopters can beprovided in addition to inducing rotationally and/or non-rotationallysymmetric aberrations. In various embodiments, the optical power and theaberration pattern provided in each eye is selected such that one eye(e.g. the dominant eye) has an extended depth of focus to provide visualacuity at far and intermediate distances and the other eye (e.g. thenon-dominant eye) has an extended depth of focus to provide visualacuity at near and intermediate distances. Improved visual acuity at anintermediate distance is obtained due to binocular summation, which is aprocess by which the brain combines the information it receives from thedominant and the non-dominant eye.

In one aspect, extended depth of focus can be obtained by implanting afirst IOL in the first eye and a second IOL in the second eye. The firstIOL is selected to have a first optical power and a first opticalaberration pattern (e.g. rotationally symmetric or non-rotationallysymmetric) to provide visual acuity above a certain threshold forobjects located at far to intermediate distances. The second IOL isselected to have a second optical power and a second optical aberrationpattern (e.g. rotationally symmetric or non-rotationally symmetric) toprovide visual acuity above a certain threshold for objects located atnear to intermediate distances. The IOLs can be monofocal or multifocal.In various embodiments, the IOLs can include diffractive features, whichmay also be rotationally symmetric or asymmetric. The IOLs may alsoinclude refractive features, which may also be rotationally symmetric orasymmetric.

In another aspect, extended depth of focus can be obtained by shapingthe cornea and/or the lens of the first eye to have a first opticalpower and a first optical aberration pattern (e.g. rotationallysymmetric or non-rotationally symmetric) to provide visual acuity abovea certain threshold for objects located at far to intermediatedistances; and shaping the cornea and/or the lens of the second eye tohave a second optical power and a second optical aberration pattern(e.g. rotationally symmetric or non-rotationally symmetric) to providevisual acuity above a certain threshold for objects located at near tointermediate distances. The shaping of the cornea or the natural lenscan be performed by known methods, such as, for example using picosecondor femtosecond laser. Laser ablation procedures can remove a targetedamount stroma of a cornea to change a cornea's contour and adjust foraberrations. In known systems, a laser beam often comprises a series ofdiscrete pulses of laser light energy, with a total shape and amount oftissue removed being determined by a shape, size, location, and/ornumber of laser energy pulses impinging on a cornea. In an alternativeembodiment, the treatment may combine laser and cataract surgery. Whileduring cataract surgery, IOLs implanted may be generating the desiredconfiguration of added powers, with either refractive or diffractiveconcepts, the combination of rotationally symmetric and non-rotationallysymmetric aberrations may be created in a posterior laser treatment thatmay be applied either in the corneal or in these implanted IOLs. In someembodiments, extended depth of focus can be provided by designing afirst lens for use in a first eye, and a second lens for use in a secondeye. The first and the second lens can be corneal implants, contactlenses or lenses for use in spectacles. The first and second lenses canbe monofocal or multifocal. The first lens has an optical power and anoptical aberration pattern that provides distant to intermediate vision.The second lens has an optical power and an optical aberration patternthat provides near to intermediate vision.

In various embodiments described herein rotationally symmetricaberrations (e.g. fourth and higher order spherical aberration terms)are induced in one eye while non-rotationally symmetric aberrations(e.g. astigmatism, coma and trefoil or combination thereof) are inducedin the other eye to provide extended depth of focus. In variousembodiments, the rotationally symmetric and non-rotationally symmetricaberrations can be superimposed over the naturally occurring aberrationsin the eye. In some embodiments, the naturally occurring aberrations inthe patient's eye may be corrected or scaled, as detailed in U.S. patentapplication Ser. No. 13/690,505 referenced above, in addition toinducing the rotationally symmetric or non-rotationally symmetricaberrations.

Rotationally symmetric aberrations, such as, for example includinghigher order spherical aberration terms can generate a uniform blur. Insome instances, this uniform blur can translate into rotationallysymmetric halos. On the other hand, non-rotationally symmetricaberrations can generate asymmetric halos which may be more tolerable ascompared to rotationally symmetric halos. Providing rotationallysymmetric aberrations in one eye and non-rotationally symmetricaberrations in the other eye can advantageously improve intermediatevision and extend depth of focus while reducing the impairments causedby rotationally symmetric halos. In some instances, combining sphericaland/or non-rotationally symmetric with monovision can also improvestereopsis, which is related to depth perception.

The amount and type of rotationally symmetric and non-rotationallysymmetric aberrations to be induced in each eye can be tested. A visualsimulator was used to study whether the amount of aberrations that canbe induced to produce a loss of one line in visual acuity is constantthrough the population. In order to do that, the monocular visual acuityof 5 subjects was measured under cyclopegic conditions when naturalaberrations were corrected and those corresponding with an averagepseudophakic eye were induced (0.15 μm RMS for a 5 mm pupil). Then, theamount of either spherical aberration or positive vertical coma thatproduced a loss of visual acuity of 0.1 Log MAR was determined when aphysical pupil of 4 mm was imposed. The threshold value for negative SAwas the smallest (−0.16±0.04 μm at 5 mm pupil induction), followed bypositive SA (0.25±0.05 μm). The custom threshold for VC was consistentlythe highest (0.78±0.12 μm), ranging from 0.70 to 0.98 μms. Therefore, itis safe to consider a threshold of vertical coma and sphericalaberration of about 0.8 μm and 0.2 μm, respectively. Those are thevalues that may be imposed as rotationally symmetric (sphericalaberration) and asymmetric (vertical coma), while possibly correctingnatural aberrations and inducing those corresponding to the averagepseudophakic eye. This application is particularly advantageous forthese eyes with a dense cataract which may increase the difficulty ofdetermining potential customized thresholds.

In another embodiment, the vision simulator can be used to individuallydetermine these monocular thresholds to both rotationally and nonrotationally symmetric aberrations. As described previously, the visualacuity can be measured at best focus for a certain pupil size (e.g. 3 mmpupil size, 4 mm pupil size, or 5 mm pupil size). Then, the letter sizemay be increased until the target visual acuity is reached (ie. thatcorresponding to the measured VA plus n*0.1 log MAR, being n is a numberbetween 0 and 3). Different values of rotationally symmetric aberrations(e.g. higher order spherical aberrations) or non-rotationally symmetricaberrations (e.g. astigmatism, coma or trefoil) are applied to the eyeand the threshold value of rotationally symmetric aberrations andnon-rotationally symmetric aberrations is determined as the maximumamount of aberration that allows for resolving that letter size, andtherefore, provides with measured VA plus n*0.1 log MAR. Once themonocular thresholds are determined for each eye, the correspondingvalues are presented binocularly to the subject. In one implementation,the binocular threshold values are the value of therotationally/non-rotationally symmetric aberration that provides thebest through focus as well as comfort for the patient. In someinstances, an optical add power (e.g. between about +0.5 Diopters and+3.0 Diopters) can be provided to the non-domination and/or the dominanteye. In an alternative embodiment, rotationally symmetric and asymmetricdiffractive designs can also be induced, for the patient to comparebetween different options.

Another example method 2000 for determining the amount and type ofrotationally symmetric and non-rotationally symmetric aberrations to beinduced in each eye is illustrated in FIG. 2A. The method includes: (i)determining with a binocular vision simulator a first maximum amount ofrotationally symmetric or non-rotationally symmetric aberration whichprovides distant vision in a first eye, as shown in block 2005; (ii)determining with the binocular vision simulator a second maximum amountof rotationally symmetric or non-rotationally symmetric aberration whichprovides near vision in a second eye, as shown in block 2010; (iii)applying the first maximum amount of rotationally symmetric ornon-rotationally symmetric aberration in the first eye, as shown inblock 2015; and (iv) applying the second maximum amount ofnon-rotationally symmetric or rotationally symmetric aberration in thesecond eye, as shown in block 2020. In various embodiments, arotationally symmetric aberration pattern is applied to the second eyeif a non-rotationally symmetric aberration pattern is applied in thefirst eye and vice-versa.

In one implementation of the method 2000 described above, the maximumamount of rotationally symmetric or non-rotationally symmetricaberration is that value selected from all possible values ofrotationally symmetric or non-rotationally symmetric aberration whichprovides the highest extended depth of focus monocularly and the highestvisual acuity at an intermediate distance binocularly. As previouslydiscussed, the method 2000 can be implemented with IOLs, cornealimplants, contact lenses, lenses for use in spectacles, etc.Alternately, the cornea or the lens of the patient can be shaped inaccordance with the method 2000 such that rotationally/non-rotationallysymmetric aberrations and an add power are induced in one eye to achievedistant vision with an extended depth of focus; androtationally/non-rotationally symmetric aberrations and an add power areinduced in the other eye to achieve near vision with an extended depthof focus.

An example of the procedure is shown at FIG. 2B, in which sphericalaberration represents rotationally symmetric aberration term andvertical coma the non-rotationally symmetric aberration term. In orderto select the treatment, the thresholds may be customized, while using avisual simulator as previously described or can be taken from thosemeasured in the average population. Once the thresholds have beendetermined monocularly, the binocular test starts. Different options areshown in FIG. 2B. For a determined letter size, corresponding to a VAbetween 0 and 0.1 Log MAR, different viewing distances (0D of defocus,corresponding to far, −1.5D of defocus corresponding to intermediate and−2.5D of defocus corresponding to far) may be shown to a subject forhim/her to subjectively judge the option that is more suitable orcomfortable. This test can be performed before cataract surgery, inorder to make a customized selection of the lens to implant for thepatient and only if the degree of cataract allows for visual simulation.The test can be also performed after the surgery, when the resultingaberration patterns or added powers may be induced as a laser treatmenteither in the cornea or the IOL itself. FIG. 2B lists potentialbinocular combinations with the first combinations utilizing a purelyrefractive (mixed monovision) platform. Symmetric diffractive platformsin combination with asymmetric diffractive platforms as seen, forexample, in FIGS. 4A1-4A5 may also be used. Symmetric refractiveplatforms along with asymmetric refractive platforms, such as seen inU.S. patent application Ser. No. 13/309,314, entitled filed on Dec. 1,2011, and incorporated herein by reference in its entirety, may also beused.

The IOLs or other ophthalmic devices discussed for use herein may beconstructed of any commonly employed material or materials used forrigid optics, such as polymethylmethacrylate (PMMA), or of any commonlyused materials for resiliently deformable or foldable optics, such assilicone polymeric materials, acrylic polymeric materials,hydrogel-forming polymeric materials, such aspolyhydroxyethylmethacrylate, polyphosphazenes, polyurethanes, andmixtures thereof and the like. The material used preferably forms anoptically clear optic and exhibits biocompatibility in the environmentof the eye. Additionally, foldable/deformable materials are particularlyadvantageous for formation of implantable ones of ophthalmic lenses foruse in the present invention, in part because lenses made from suchdeformable materials may be rolled, folded or otherwise deformed andinserted into the eye through a small incision.

In addition to providing visual acuity at near, intermediate and fardistances, the ophthalmic solutions (e.g. IOLs, contact lenses, cornealimplants, etc.) used herein can correct for other conditions of the eye.For example, the ophthalmic solution can be a toric lens for correctingastigmatism and include rotationally/non-rotationally symmetricaberrations to provide enhanced visual acuity. As another example, theophthalmic solution can be an aspheric lens includingrotationally/non-rotationally symmetric aberrations to provide enhancedvisual acuity. As yet another example, the ophthalmic solution can be acombination of refractive and diffractive features that arerotationally/non-rotationally symmetric to provide enhanced visualacuity.

The methods described herein can be performed by using instruments thatare known to a person having ordinary skill in the art. An instrument toimplement the methods described herein can comprise a set ofapparatuses, including a set of apparatuses from different manufacturersthat are configured to perform the necessary measurements andcalculations. Any instrument comprising all needed measurements (ocularand corneal wavefront aberration measurements) as well as the neededcalculations to implement the methods described herein, including butnot limited to the method 2000 can be considered as an inventiveembodiment. FIG. 3 is a block diagram illustrating an embodiment of aclinical system 3000 that can be used to implement the methods describedherein, including but not limited to the method 2000. The system 3000includes one or more apparatuses capable of performing the calculations,assessments and comparisons set forth in determining therotationally/non-rotationally symmetric aberration patterns and the addpower that provide enhanced visual acuity at near, intermediate and fardistances. The system 3000 may include a biometric reader 3001 (e.g. abinocular vision simulator), a processor 3002, and a computer readablememory or medium 3004 coupled to the processor 3002. The computerreadable memory 3004 includes therein an array of ordered values 3008and sequences of instructions 3010 which, when executed by the processor3002, cause the processor 3002 to select therotationally/non-rotationally symmetric aberration pattern that providesdistant vision with an extended depth of focus in one eye and nearvision with an extended depth of focus in the other eye such that anenhanced visual acuity at an intermediate distance is obtained bybinocular summation.

The array of ordered values 3008 can include one or more desiredrefractive outcomes, data obtained from measurements of the patient'seye, data related to one or more types of available ophthalmicsolutions, a set of all possible rotationally/non-rotationally symmetricaberration patterns, parameters of refractive and diffractive features,etc. In some embodiments, the sequence of instructions 3010 can includealgorithms to perform calculations, customization, simulation,comparison, etc.

The processor 3002 may be embodied in a general purpose desktop, laptop,tablet or mobile computer, and/or may comprise hardware and/or softwareassociated with inputs 3001. In certain embodiments, the system 3000 maybe configured to be electronically coupled to another device, such asone or more instruments for obtaining measurements of an eye or aplurality of eyes. Alternatively, the system 3000 may be adapted to beelectronically and/or wirelessly coupled to one or more other devices.

The system illustrated in FIG. 3 can be used for selecting therotationally/non-rotationally symmetric optical aberration patterns inblocks 2005 and 2010 of the method 2000. For example, the clinicalmeasurements provided by the reader 3001, can be used to determine whichrotationally/non-rotationally symmetric optical treatments stored in theprocessor 3002 provides distant vision with an extended depth of focusin one eye and near vision with an extended depth of focus in the othereye such that an enhanced visual acuity at an intermediate distance isobtained by binocular summation.

As discussed above, the methods described herein can be implemented inlenses (e.g. IOLs, contact lenses, lenses for use with spectacles,etc.). For example, in some embodiments, the lenses can be monofocallenses that provide distant or near vision that includerotationally/non-rotationally symmetric aberration pattern for providingvisual acuity for object located at intermediate distance. As anotherexample, in some embodiments, the lenses can be multifocal lensesproviding distant and near vision and further includingrotationally/non-rotationally symmetric aberration pattern for providingvisual acuity for object located at intermediate distance. As yetanother example, in some embodiments, the lenses can have refractive ordiffractive features that are symmetric or asymmetric such that improvedvisual acuity at near, intermediate and far distances is obtained. Someexamples of lenses including rotationally asymmetric features thatprovide improved visual acuity at near, intermediate and far distancesare discussed below with reference to FIGS. 4A1-4A5. As discussed above,rotationally symmetric aberrations can include higher order (e.g. 4^(th)and 6^(th) order) spherical aberrations. As discussed above,non-rotationally symmetric aberrations can include astigmatism, coma ortrefoil.

By way of example, FIGS. 4A1-4A5 shows various embodiments of lensesincluding rotationally asymmetric diffractive features. The lensesillustrated in FIGS. 4A1-4A5 include a plurality of partially annularstructures. The partially annular structures can be distributed around acentral optical zone disposed about an optical axis. In someembodiments, the optical zone between two consecutive partially annularstructures can have an optical power that is equal to the optical powerof the central zone. In some other embodiments, the optical zone betweentwo consecutive partially annular structures can have an optical powerthat is different from the optical power of the central zone. Each ofthe partially annular structure can include microstructures that arediffractive or refractive. Each of the partially annular structure canhave a vertical and horizontal profile that determines the overalloptical power of the lens and the distribution of light between thevarious optical zones.

In FIG. 4A1, region A1 includes a plurality of semi-annular structuresthat cover about 50% of the surface area of the ophthalmic lens. Theupper part of the lens has 50% light distribution between 1D and 2D addpower, while the rest has an asymmetric light distribution between thesame add powers. In various embodiments, the portion of the ophthalmiclens below the region A1 can be devoid of microstructures or includemicrostructures similar to the microstructures in the region A1, suchthat the ophthalmic lens illustrated in FIG. 4A1 is rotationallysymmetric. In an alternative embodiment, the lower part may be composedby a different diffractive designs which provides different add powersand light distributions.

FIG. 4A2 illustrates an ophthalmic lens including a first region A2having partially annular structures with an add power of 1D, beingessentially monofocal, and a second region B2 having partially annularstructures with an add power of 2D, also monofocal. The regions A2 andB2 can each occupy about 25% of the surface area of the ophthalmic lens,while the remaining approximately 50% of the lens has a 0D add power andits basically refractive monofocal.

FIG. 4A3 illustrates an ophthalmic lens including a first region A3having partially annular structures with an add power of 2D, beingessentially monofocal, a second region B3 having partially annularstructures with an add power of 3D, being essentially monofocal, and athird region C3 having partially annular structures with an add power of1D, being essentially monofocal. The regions A3 and B3 can each occupyabout 25% of the surface area of the ophthalmic lens and the region C3can occupy about 50% of the surface area of the ophthalmic lens. Thearea occupied by every different sector can be modified as shown in FIG.4A4, where each region subtends the same area. In an alternativeembodiment, at FIG. 4A5, the area occupied by the region with an addpower of 1D is greater than for the rest.

Although the invention has been described and pictured in an exemplaryform with a certain degree of particularity, it should be understoodthat the present disclosure of the exemplary form has been made by wayof example, and that numerous changes in the details of construction andcombination and arrangement of parts and steps may be made withoutdeparting from the spirit and scope of the invention as set forth in theclaims hereinafter.

What is claimed is:
 1. A method of treating presbyopia comprising:providing a first intraocular lens for implantation that induces apredetermined amount of fourth or higher order spherical aberration in afirst eye of a patient; providing a second intraocular lens forimplantation that induces a predetermined amount of astigmatism in asecond eye of the patient; implanting the first intraocular lens intothe first eye of the patient; implanting the second intraocular lensinto the second eye of the patient; wherein the predetermined amount offourth or higher order spherical aberration is only induced in the firsteye, and the predetermined amount of astigmatism is induced only in thesecond eye; and further wherein the predetermined amounts of sphericalaberration and astigmatism collectively enhance acuity at anintermediate distance.
 2. The method of claim 1, further comprisingproviding correction in the first eye to provide a defocus for near orintermediate vision in the first eye.
 3. The method of claim 1, furthercomprising providing correction in the second eye to provide distancevision in the second eye.